High-Temperature Oxidation Resistance of Mg-Ca Alloys in Air and Under Flame Exposure

Abstract:

The oxidation behavior and mechanism of Mg-Ca alloys in air and under flame exposure were studied. Results show that for the oxidation in air, the Mg-Ca-O oxide film with Ca accumulation and low Mg vapor pressure on the surface of Mg-Ca alloys with high Ca content shows good protective effect. However, the falling off phenomenon of the oxide film on Mg₂Ca results in the further oxidation. Hence, the Mg-Ca alloys with high Ca content only show good protective effect. For the oxidation in flame, the molten alloys release the Ca atoms to diffuse outward. The Mg-Ca-O oxide film with high Ca accumulation layer forms in Mg-Ca alloys with high Ca content. Despite the high Mg vapor pressure in the molten alloy, the Mg-Ca-O oxide film with high Ca accumulation layer shows excellent protective effect.